The present embodiments relate to a magnetic resonance tomography (MRT) local coil for an MRT system.
MRT devices for examining objects or patients using magnetic resonance tomography (e.g., MRT, MRI) are known, for example, from DE10314215B4.
In MR tomography with a magnetic resonance tomography device (MR or MRT), images with a high signal to noise ratio (SNR) may be recorded using local coils. The local coils are antenna systems positioned in direct proximity on (anterior) or below (posterior) the patient. During an MR measurement, excited nuclei in the individual antennas of the local coil induce a voltage that is amplified using a low-noise preamplifier (e.g., LNA, preamp) and forwarded by cable to an electronic receive system. To improve the signal to noise ratio even with high-resolution images, high-field systems are used (e.g., 1.5 T to 12 T and more). Since more individual antennas may be connected to an MR receive system than there are receivers present, a switching matrix (e.g., RCCS) is incorporated between receive antennas and receivers. This routes the currently active receive channels (e.g., the receive channels present in the field of view (FoV) of the magnet at the time) to the receivers present. This allows more coil elements to be connected than there are receivers present, since for whole body coverage, only the coils present in the FoV or the homogeneity volume of the magnet are to be read out.
A “coil” or a “local coil” may be, for example, an antenna system that may include one or a plurality (e.g., in the case of an array coil) of antenna elements (or “coil elements”). These individual antenna elements may be configured as loop antennas (loops), butterfly coils or saddle coils. A coil includes, for example, the coil elements, a preamplifier, further electronics (e.g., baluns) and cabling, a housing and may include a cable with a plug (e.g., used to connect the coil to the MRT system). A receiver (RX) on the system side filters and digitizes a signal received from the local coil and transmits the digitized signal to a digital signal processor that may derive an image or a spectrum from the measurement. The digital signal processor may make the image or the spectrum available to the user for diagnosis purposes.
In interventional radiology, for example, it is possible or advantageous to perform imaging (e.g., MR imaging) using local coils and the intervention at the same time or almost at the same time, or at least to leave intervention instruments (e.g., needles, catheters, ablation instruments, biopsy needles) and coils set up in positions during the individual work steps. The coils may cover access to the patient to some extent. With coils that permit mechanical openings between the antenna structures, imaging and intervention may take place through the opening, and an antenna that encloses (e.g., surrounds) the site of the intervention is even advantageous for image quality.
According to the prior art, for example, two coils are each disposed to the side of the access point so that the two coils may also be removed laterally (e.g., by pushing to the side and/or in the x direction) when an instrument (e.g., person, animal) that extends out of the examination object in a direction orthogonal to the plane of a coil (and/or the y direction) is present in the examination object.